Image signal processing device, transmitting device, image signal processing method, program and image signal processing system

ABSTRACT

An image signal processing device is provided which includes a receiving unit for receiving an image signal and setting information for each predetermined unit of the image signal including image type setting information to define whether the image signal represents a stereoscopic image and gamma correction setting information to define a gamma correction amount for the image signal, a gamma correcting unit for performing gamma correction for the image signal based on the gamma correction setting information included in the setting information received by the receiving unit, and a stereoscopic image processing unit for selectively performing a process to display the stereoscopic image for the image signal corrected by the gamma correcting unit based on the image type setting information included in the setting information received by the receiving unit.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. patent applicationSer. No. 12/807,699, filed Sep. 10, 2010, which claims priority fromJapanese Patent Application No. JP 2009-215852 filed in the JapanesePatent Office on Sep. 17, 2009, the disclosures of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image signal processing device, atransmitting device, an image signal processing method, a program and animage signal processing system.

2. Description of the Related Art

In recent years, a display device capable of processing an image signal(right-eye image signal and left-eye image signal) representing astereoscopic image to display the stereoscopic image on a display screenhas been developed. There is a configuration to allow a user to visuallyrecognize the stereoscopic image in cooperation with an external devicesuch as polarization glasses and liquid crystal shutter glasses, aconfiguration provided with a mechanism related to parallax barrier(configuration without using the external device) and the like, forexample, as the configuration to allow the user to recognize the imagedisplayed on the display device as the stereoscopic image.

In these circumstances, technology to realize a high quality image inboth of a case in which the stereoscopic image is displayed on thedisplay screen and a case in which a flat image is displayed on thedisplay screen has been developed. For example, the Japanese PatentApplication Laid-Open No. 2007-65067 discloses the technology to judgewhether it is the stereoscopic image based on the image signal andcontrol a light-emission pattern of a light source provided in thedisplay device based on a judgment result.

BRIEF SUMMARY OF THE INVENTION

When the display device for displaying the stereoscopic image on thedisplay screen is configured to allow the user to visually recognize thestereoscopic image in cooperation with the external device such as thepolarization glasses and the liquid crystal shutter glasses, an amountof light entering eyes of the user might decrease according to a type ofthe external device. For example, when the display device displays thestereoscopic image by a method of alternatively displaying a right-eyeimage (image represented by the right-eye image signal) and a left-eyeimage (image represented by the left-eye image signal) in a direction oftime and the user watches the image with the liquid crystal shutterglasses, there is a case in which the amount of light entering the eyesof the user through the liquid crystal shutter glasses might decrease.In the above-described case, the image watched by the user becomes darkas a whole due to deficiency of the amount of light, so that eyestrainof the user might occur.

The display device performs light source control and control ofbrightness gradient, for example, as a method of preventing the amountof light entering the eyes of the user from decreasing. However, whenthe light source control and the control of the brightness gradient arefreely performed on a display device side, a portion in the image, whichshould be dark, becomes too bright, for example, and intention of acontents (movie and game, for example) author side related to the imagedisplayed on the display screen might not be sufficiently reflected onthe image watched by the user. Therefore, in the above-described case,even when it is possible to prevent the amount of light entering theeyes of the user from decreasing when the image signal is displayed onthe display screen, there is no certainty that the high quality image(high quality image in a viewpoint that the intention of the contentsauthor side is faithfully reproduced, same in the following) issufficiently realized.

Herein, the related technology to try to realize the high quality imagein both of the case of displaying the stereoscopic image on the displayscreen and the case of displaying the flat image on the display screen(hereinafter, referred to as the “related technology”) controls alight-emission pattern of the light source provided in the displaydevice based on the judgment result of the image type based on the imagesignal. However, the related technology merely control the lightemission-pattern of the light source such that the amount of lightentering the eyes of the user is the same when displaying the flat image(2D image) and when displaying the stereoscopic image (3D image).Therefore, there is no certainty that the high quality image issufficiently realized as in the method of preventing the amount of lightentering the eyes of the user from decreasing even when the relatedtechnology is used.

In light of the foregoing, it is desirable to provide a novel andimproved image signal processing device, transmitting device, imagesignal processing method, program and image signal processing systemcapable of realizing the high quality image while preventing the amountof light entering the eyes of the user from decreasing when the imagesignal is displayed on the display screen.

According to an embodiment of the present invention, there is providedan image signal processing device, including a receiving unit forreceiving an image signal and setting information for each predeterminedunit of the image signal including image type setting information todefine whether the image signal represents a stereoscopic image andgamma correction setting information to define a gamma correction amountfor the image signal, a gamma correcting unit for performing gammacorrection for the image signal based on the gamma correction settinginformation included in the setting information received by thereceiving unit, and a stereoscopic image processing unit for selectivelyperforming a process to display the stereoscopic image for the imagesignal corrected by the gamma correcting unit based on the image typesetting information included in the setting information received by thereceiving unit.

According to such configuration, it becomes possible to process thereceived image signal and selectively perform the control of thebrightness gradient based on the received setting information.Therefore, according to such configuration, it becomes possible torealize the high quality image while preventing the amount of lightentering the eyes of the user from decreasing when the image signal isdisplayed on the display screen.

The gamma correcting unit may selectively perform the gamma correctionbased on the gamma correction setting information based on processexecuting information related to execution of a process being stored.

The image signal processing device may further include a display unitfor displaying an image corresponding to the image signal output fromthe stereoscopic image processing unit on a display screen and iscapable of adjusting brightness for each part of the display screen, anda brightness controller for transferring a brightness control signal forcontrolling the brightness of the each part of the display screen to thedisplay unit. The setting information may further include brightnesssetting information to define the brightness of each part of the displayscreen, and the brightness controller may transfer the brightnesscontrol signal based on the brightness setting information included inthe setting information received by the receiving unit to the displayunit.

According to an embodiment of the present invention, there is provided atransmitting device, including a setting unit for setting set values tobe set in image type setting information to define whether an imagesignal to be transmitted represents a stereoscopic image, gammacorrection setting information to define a gamma correction amount forthe image signal to be transmitted and/or brightness setting informationto define brightness of each part of a display screen for eachpredetermined unit of the image signal to be transmitted based on theimage signal to be transmitted, a transmission signal generating unitfor generating a transmission signal including the image signal to betransmitted and setting information for each predetermined unit of theimage signal to be transmitted including the image type settinginformation, the gamma correction setting information and/or thebrightness setting information based on the image signal to betransmitted and the set values for each predetermined unit of the imagesignal to be transmitted set by the setting unit, and a transmittingunit for transmitting the transmission signal generated by thetransmission signal generating unit.

According to such configuration, it becomes possible to generate thesetting information for each predetermined unit of the image signalbased on the image signal to be transmitted to transmit the image signaland the setting information. Therefore, according to such configuration,it becomes possible to realize the high quality image while preventingthe amount of light entering the eyes of the user from decreasing whenthe image signal is displayed on the display screen.

The setting unit may judge whether the image signal to be transmittedrepresents the stereoscopic image, and when it is judged that the imagesignal to be transmitted represents the stereoscopic image, may set theset values based on a brightness average value based on the image signalto be transmitted for each divided area obtained by dividing an areacorresponding to a display screen.

The setting unit may derive degree distribution of brightness averagevalues for each divided area and may set the set values based on thederived degree distribution and one or two or more predeterminedthreshold.

According to an embodiment of the present invention, there is providedan image signal processing method, including the steps of receiving animage signal and setting information for each predetermined unit in theimage signal including image type setting information to define whetherthe image signal represents a stereoscopic image and gamma correctionsetting information to define a gamma correction amount for the imagesignal, performing gamma correction for the image signal based on thegamma correction setting information included in the setting informationreceived in the step of receiving, and selectively performing a processto display the stereoscopic image for the image signal corrected in thestep of performing the gamma correction based on the image type settinginformation included in the setting information received in the step ofreceiving.

By using such method, it becomes possible to realize the high qualityimage while preventing the amount of light entering the eyes of the userfrom decreasing when the image signal is displayed on the displayscreen.

According to an embodiment of the present invention, there is provided aprogram for causing a computer to execute the steps of receiving animage signal and setting information for each predetermined unit of theimage signal including image type setting information to define whetherthe image signal represents a stereoscopic image and gamma correctionsetting information to define a gamma correction amount for the imagesignal, performing gamma correction for the image signal based on thegamma correction setting information included in the setting informationreceived in the step of receiving, and selectively performing a processto display the stereoscopic image for the image signal corrected in thestep of performing the gamma correction based on the image type settinginformation included in the setting information received in the step ofreceiving.

By using such program, it becomes possible to realize the high qualityimage while preventing the amount of light entering the eyes of the userfrom decreasing when the image signal is displayed on the displayscreen.

According to an embodiment of the present invention, there is providedan image signal processing system, including a transmitting deviceincluding a setting unit for setting set values to be set in image typesetting information to define whether an image signal to be transmittedrepresents a stereoscopic image and gamma correction setting informationto define a gamma correction amount for the image signal to betransmitted for each predetermined unit of the image signal to betransmitted based on the image signal to be transmitted, a transmissionsignal generating unit for generating a transmission signal includingthe image signal to be transmitted and setting information for eachpredetermined unit of the image signal to be transmitted including theimage type setting information and the gamma correction settinginformation based on the image signal to be transmitted and the setvalues for each predetermined unit of the image signal to be transmittedset by the setting unit, and a transmitting unit for transmitting thetransmission signal generated by the transmission signal generatingunit, and an image signal processing device including a receiving unitfor receiving the transmission signal, a gamma correcting unit forperforming gamma correction for the image signal included in thetransmission signal received by the receiving unit based on the gammacorrection setting information included in the setting informationincluded in the transmission signal received by the receiving unit, anda stereoscopic image processing unit for selectively performing aprocess to display the stereoscopic image for the image signal correctedby the gamma correcting unit based on the image type setting informationincluded in the setting information included in the transmission signalreceived by the receiving unit.

According to such configuration, the image signal processing systemcapable of realizing the high quality image while preventing the amountof light entering the eyes of the user from decreasing when the imagesignal is displayed on the display screen is realized.

According to an embodiment of the present invention, it becomes possibleto realize the high quality image while preventing the amount of lightentering the eyes of the user from decreasing when the image signal isdisplayed on the display screen.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory diagram for illustrating an overview of a highquality image approach according to an embodiment of the presentinvention;

FIG. 2 is an explanatory diagram for illustrating an overview of a highquality image approach according to an embodiment of the presentinvention;

FIG. 3 is an explanatory diagram for illustrating an overview of a highquality image approach according to an embodiment of the presentinvention;

FIG. 4 is an explanatory diagram for illustrating an overview of a highquality image approach according to an embodiment of the presentinvention;

FIG. 5 is an explanatory diagram illustrating an example of gammacorrection setting information generated by a transmitting deviceaccording to the embodiment of the present invention;

FIG. 6 is an explanatory diagram illustrating an example of brightnesssetting information generated by the transmitting device according tothe embodiment of the present invention;

FIG. 7 is an explanatory diagram for illustrating an overview of animage signal processing system according to the embodiment of thepresent invention;

FIG. 8 is an explanatory diagram for illustrating an example of aconfiguration of the transmitting device according to the embodiment ofthe present invention;

FIG. 9 is a flowchart illustrating an example of a setting process in asetting unit of the transmitting device according to the embodiment ofthe present invention;

FIG. 10 is an explanatory diagram illustrating an example of image typesetting information generated by the transmitting device according tothe embodiment of the present invention;

FIG. 11 is an explanatory diagram for illustrating a first example of aconfiguration of an image signal processing device according to theembodiment of the present invention;

FIG. 12 is an explanatory diagram illustrating an example of aconfiguration of a receiving unit provided in the image signalprocessing device according to the embodiment of the present invention;

FIG. 13 is an explanatory diagram for illustrating a second example of aconfiguration of an image signal processing device according to theembodiment of the present invention;

FIG. 14 is an explanatory diagram for illustrating an example of aconfiguration of the transmitting device according to the embodiment ofthe present invention;

FIG. 15 is an explanatory diagram illustrating an example of atransmission signal transmitted by a receiving device according to theembodiment of the present invention; and

FIG. 16 is an explanatory diagram illustrating an example of atransmission signal transmitted by a receiving device according to theembodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENT(S)

Hereinafter, preferred embodiments of the present invention will bedescribed in detail with reference to the appended drawings. Note that,in this specification and the appended drawings, structural elementsthat have substantially the same function and structure are denoted withthe same reference numerals, and repeated explanation of thesestructural elements is omitted.

Hereinafter, a description will be made in the following order.

1. Approach according to embodiment of the present invention

2. Image signal processing system according to embodiment of the presentinvention

3. Program according to embodiment of the present invention

(Approach According to Embodiment of the Present Invention)

A high-quality image approach according to an embodiment of the presentinvention is described before describing a configuration of each device,which composes an image signal processing system (hereinafter, sometimesreferred to as a “image signal processing system 1000”) according to theembodiment of the present invention.

As described above, when using a method of preventing an amount of lightentering eyes of a user from decreasing and the related technology, animage displayed on a display screen and watched by the user might notsufficiently reflect intention of a contents author side.

Then, in the image signal processing system 1000, a transmitting device(hereinafter, sometimes referred to as a “transmitting device 100”)according to the embodiment of the present invention for transmitting animage signal generates setting information for each predetermined unitof the image signal based on the image signal to be transmitted andtransmits the setting information together with the image signal.Hereinafter, a signal including the image signal and the settinginformation for each predetermined unit of the image signal transmittedby the transmitting device 100 is sometimes collectively referred to asa “transmission signal”.

In the image signal processing system 1000, an image signal processingdevice (hereinafter, sometimes referred to as a “image signal processingdevice 200”) according to the embodiment of the present invention, whichreceives the image signal and the setting information, processes thereceived image signal and selectively performs control of brightnessgradient and/or light source control of a display device based on thereceived setting information.

Meanwhile, in the image signal processing system 1000 according to theembodiment of the present invention, the transmitting device 100 maytransmit an audio signal related to audio corresponding to the imagerepresented by the image signal together with the image signal, and theimage signal processing device 200 may process the audio signal.Hereinafter, a process related to the transmission of the audio signalin the transmitting device 100 and a process related to the process ofthe audio signal in the image signal processing device 200 are notdescribed.

Herein, although there is a digital signal such as a bit stream signalas the image signal according to the embodiment of the presentinvention, for example, this is not limited to the above description,and may be an analog signal. Hereinafter, a case in which the imagesignal according to the embodiment of the present invention is thedigital signal is described as an example. Further, the imagerepresented by the image signal according to the embodiment of thepresent invention may be a moving image (flat image/stereoscopic image)and may be a still image (flat image/stereoscopic image).

The predetermined unit of the image signal according to the embodimentof the present invention is a temporally completed unit of the imagesignal, for example. Although there is a frame, one image unit in aninterlace method, one image unit in a progressive method and the like,for example, as the predetermined unit of the image signal according tothe embodiment of the present invention, this is not limited to theabove description. For example, the predetermined unit of the imagesignal according to the embodiment of the present invention may be aplurality of frames.

The setting information according to the embodiment of the presentinvention includes image type setting information, gamma correctionsetting information and/or brightness setting information. Herein,although the transmitting device 100 may transmit the image type settinginformation, the gamma correction setting information and the brightnesssetting information according to the embodiment of the present inventionas one setting information (data), for example, this is not limited tothe above description. For example, the transmitting device 100 maytransmit the image type setting information, the gamma correctionsetting information and the brightness setting information as separatesetting information. In the embodiment of the present invention, both ofa case in which the transmitting device 100 transmits various pieces ofinformation as one setting information and a case in which thistransmits them as separate setting information as described above aredescribed assuming that “the setting information includes the image typesetting information, the gamma correction setting information and/or thebrightness setting information”.

The image type setting information according to the embodiment of thepresent invention is information to define whether the image signalrepresents the stereoscopic image. The image type setting information isused by the image signal processing device 200 to selectively perform aprocess to display the stereoscopic image. An example of the image typesetting information according to the embodiment of the present inventionwill be described later.

Further, the gamma correction setting information according to theembodiment of the present invention is information to define a gammacorrection amount for the image signal. The gamma correction settinginformation is used by the image signal processing device 200 to performthe control of the brightness gradient. An example of the gammacorrection setting information according to the embodiment of thepresent invention will be described later.

Further, the brightness setting information according to the embodimentof the present invention is information to define the brightness of eachpart of the display screen. The brightness setting information is usedby the image signal processing device 200 to perform the light sourcecontrol of the display device. An example of the brightness settinginformation according to the embodiment of the present invention will bedescribed later.

Herein, there is a divided area obtained by dividing the imagerepresented by the image signal into a plurality of areas, for example,as the above-described part of the display screen. Although there is thearea obtained by dividing for each pixel of the display device composingthe display screen, for example, as the above-described divided area,this is not limited to the above description and this may be the areahaving a plurality of pixels. Further, the above-described part of thedisplay screen may be a part corresponding to a control unit of thedisplay device of which light emission is controlled by the image signalprocessing device 200 using a brightness control signal to be describedlater.

More specifically, in the image signal processing system 1000, the imagesignal processing device selectively performs the control of thebrightness gradient and/or the light source control of the displaydevice based on the received setting information such that when theimage represented by the image signal is displayed on the displayscreen, brightness of a low-brightness portion of the image becomeshigher.

FIGS. 1 to 4 are explanatory diagrams for illustrating an overview ofthe high-quality image approach according to the embodiment of thepresent invention.

[a] Case in which Image Signal Processing Device 200 does not PerformControl of Brightness Gradient and Light Source Control of DisplayDevice Based on Setting Information

FIG. 1 illustrates an example of the gamma correction in the imagesignal processing device 200 and illustrates an example of the imagesignal when the image signal processing device 200 does not perform thecontrol of the brightness gradient and the light source control of thedisplay device based on the setting information. FIG. 1A represents anexample of a gamma property in the transmitting device 100 and FIG. 1Brepresents an example of a gamma correction function in the image signalprocessing device 200. FIG. 1C represents an example of the image signalafter the gamma correction in the image signal processing device 200.Further, FIG. 2 illustrates an example when the image represented by theimage signal to which the gamma correction illustrated in FIG. 1 isperformed is displayed on the display screen in the image signalprocessing device 200.

As represented in FIGS. 1A to 1C, when the image signal processingdevice 200 does not perform the control of the brightness gradient andthe light source control of the display device based on the settinginformation, the image signal processed by the image signal processingdevice 200 becomes the image true to the image represented by the imagesignal transmitted by the transmitting device 100 by the gammacorrection (FIG. 2).

Herein, the gamma correction in the image signal processing device 200is performed by a following equation 1, for example. “x” in the equation1 represents the image signal to be processed and “y” in the equation 1represents the image signal after the gamma correction. Further, “γ” inthe equation 1 represents a gamma correction value. Herein, although theequation 1 represents an example of the gamma correction when thebrightness is divided into 255 levels, this is not limited to the abovedescription.

$\begin{matrix}{\left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\mspace{515mu}} & \; \\{y = {255 \cdot \left( \frac{x}{255} \right)^{\frac{1}{\gamma}}}} & \left( {{equation}\mspace{14mu} 1} \right)\end{matrix}$

The image signal processing device 200 sets the gamma correction valueto a value corresponding to the gamma property in the transmittingdevice 100 (for example, when the image signal is transmitted bybroadcast wave of television broadcasting, γ=2.2 is set), therebyobtaining the image signal represented in FIG. 1C.

[b] Case in which Image Signal Processing Device 200 Performs Control ofBrightness Gradient and Light Source Control of Display Device Based onthe Setting Information

FIG. 3 illustrates an example of the image signal when the image signalprocessing device 200 performs the control of the brightness gradientand/or the light source control of the display device based on thereceived setting information. Further, FIG. 4 illustrates an examplewhen the image represented by the image signal illustrated in FIG. 3 isdisplayed on the display screen in the image signal processing device200.

As illustrated in FIG. 3, the image signal processing device 200performs the control of the brightness gradient and/or the light sourcecontrol of the display device based on the setting information such thatthe brightness of the low-brightness portion becomes higher. The imagesignal processing device 200 performs the control of the brightnessgradient and/or the light source control of the display device such thatthe brightness of the low-brightness portion becomes higher, andaccordingly, the image displayed on the display screen becomes the imageof which brightness is higher than that of the image illustrated in FIG.2, as illustrated in FIG. 4, for example.

[Example of Method of Controlling Brightness Gradient in Image SignalProcessing Device 200]

The image signal processing device 200 controls the brightness gradientby setting the value of the gamma correction value γ used in the gammacorrection based on the gamma correction setting information included inthe received setting information, for example.

FIG. 5 is an explanatory diagram illustrating an example of the gammacorrection setting information generated by the transmitting device 100according to the embodiment of the present invention. Herein, FIG. 5illustrates an example of the gamma correction setting informationaccording to video usability information (VUI) defined in the ISO/IEC14490-10.

The transmitting device 100 sets the gamma correction value in“transfer_characteristics” illustrated in FIG. 5 capable of defining aphotoelectric transfer function. Although the transmitting device 100herein directly sets the gamma correction value such as“transfer_characteristics=2.2” and “transfer_characteristics=2.8”, forexample, this is not limited to the above description. For example, inthe VUI of the ISO/IEC 14490-10, applicative definition of contentsbecomes possible by setting to “transfer_characteristics=2”. Therefore,the transmitting device 100 may set an optional gamma correction valuesuch as 2.4 by setting as “transfer_characteristics=2” as describedabove.

Meanwhile, it goes without saying that the gamma correction settinginformation according to the embodiment of the present invention is notlimited to the example illustrated in FIG. 5.

The image signal processing device 200 may perform the control of thebrightness gradient based on the setting information by performing thegamma correction using the gamma correction value set in the gammacorrection setting information included in the received settinginformation.

Meanwhile, the method of controlling the brightness gradient in theimage signal processing device 200 according to the embodiment of thepresent invention is not limited to the above description. For example,the image signal processing device 200 according to the embodiment ofthe present invention may selectively adjust a gain of the image signalfor each pixel based on gain adjusting information to define an amountof adjustment of the gain included in the setting information afterobtaining the image signal represented in FIG. 1C by the gammacorrection.

[Example of Method of Controlling Light Source of Display Device inImage Signal Processing Device 200]

The image signal processing device 200 generates the brightness controlsignal to control the brightness of each part of the display screen inthe display device capable of displaying the image on the display screenfor each part based on the brightness setting information included inthe received setting information, for example. The image signalprocessing device 200 then transfers the generated brightness controlsignal to the display device capable of displaying the image on thedisplay screen.

The light emission in the display device is controlled according to thebrightness control signal by the transfer of the brightness controlsignal to the display device. Therefore, the image signal processingdevice 200 may transfer the brightness control signal based on thebrightness setting information included in the setting information tothe display device, thereby controlling the light emission in a lightsource of the display device.

Herein, although the display device to which the brightness controlsignal generated by the image signal processing device 200 istransferred may be provided in the image signal processing device 200,for example, this is not limited to the above description. For example,the image signal processing device 200 may transmit the generatedbrightness control signal to the display device as an external device.When the image signal processing device 200 is provided with the displaydevice (corresponding to a display unit to be described later), theimage signal processing device 200 serves as the display device.

Although there is a liquid crystal display (LCD) having the light sourcecapable of emitting light for each area corresponding to each pixel or aplurality of pixels, for example, as the display device according to theembodiment of the present invention, this is not limited to the abovedescription. For example, the display device according to the embodimentof the present invention may be a self-emitting type display devicewithout a separate light source such as an organic electroluminescencedisplay (organic EL display, also referred to as an organic lightemitting diode display (OLED display)). Hereinafter, a case in which theimage signal processing device 200 generates the brightness controlsignal to control the light emission in the light source provided in thedisplay device is described as an example.

FIG. 6 is an explanatory diagram illustrating an example of thebrightness setting information generated by the transmitting device 100according to the embodiment of the present invention. Herein, FIG. 6illustrates an example of the brightness setting information accordingto User_data_unregistered SEI (supplemental enhancement information)defined in the ISO/IEC 14496-10.

Herein, “MacroBlock_ID” illustrated in FIG. 6 is information to identifya macroblock (example of the divided area) in the image represented bythe image signal. A numerical value given in a scan order and in anascending order from upper left to lower right is set in “MacroBlock_ID”illustrated in FIG. 6, for example. Therefore, the image signalprocessing device 200, which receives the brightness settinginformation, may uniquely distinguish a horizontal-vertical position bythe above-described numerical value.

Further, the transmitting device 100 sets information of an averagebrightness level of the macroblock (example of the divided area)corresponding to each “MacroBlock_ID” illustrated in FIG. 6 in“Averaged_Luma_level” illustrated in FIG. 6. Therefore, the image signalprocessing device 200, which receives the brightness settinginformation, may uniquely specify a brightness level to be set for eachmacroblock (example of the divided area), so that this may generate thebrightness control signal corresponding to the brightness settinginformation for each part of the display screen.

Meanwhile, it goes without saying that the brightness settinginformation according to the embodiment of the present invention is notlimited to the example illustrated in FIG. 6.

The image signal processing device 200 may generate the brightnesscontrol signal for each part (each divided area) of the display screenusing information of the brightness level for each divided area set inthe brightness setting information included in the received settinginformation to transfer to the display device, thereby controlling thelight emission in the light source of the display device based on thesetting information. Meanwhile, it goes without saying that the methodof controlling the light source of the display device in the imagesignal processing device 200 according to the embodiment of the presentinvention is not limited to above description.

In the image signal processing system 1000, the control of thebrightness gradient and/or the light source control of the displaydevice is performed as described above, for example, in the image signalprocessing device 200. Therefore, in the image signal processing system1000, the amount of light entering the eyes of the user may be preventedfrom decreasing when the image processed by the image signal processingdevice 200 is displayed on the display screen of the display device.

Further, in the image signal processing system 1000, the image signalprocessing device 200 performs the control of the brightness gradientand/or the light source control of the display device based on thesetting information transmitted by the transmitting device 100 asdescribed above. That is to say, in the image signal processing device200 according to the embodiment of the present invention, the control ofthe brightness gradient and/or the light source control of the displaydevice is not freely performed based on the received image signal as inthe case of using the method of preventing the amount of light enteringthe eyes of the user from decreasing.

Therefore, in the image signal processing system 1000, possibility thatthe image displayed on the display screen and watched by the user doesnot sufficiently reflect the intention of the contents author side maybe further reduced, so that the higher quality image may be realized.

Meanwhile, it goes without saying that the image signal processingdevice 200 according to the embodiment of the present invention isfurther capable of performing the above-described control by useroperation using an operating device provided in the image signalprocessing device 200, for example, in addition to the control of thebrightness gradient and/or the light source control of the displaydevice based on the received setting information. In a case of theabove-described configuration, the image signal processing systemaccording to the embodiment of the present invention may reflectintention of the user who watches the image while reflecting theintention of the contents author side on the image displayed on thedisplay screen and watched by the user.

As described above, in the image signal processing system 1000, thetransmitting device 100 transmits the image signal and the settinginformation for each predetermined unit. The image signal processingdevice 200 then processes the received image signal and selectivelyperforms the control of the brightness gradient and/or the light sourcecontrol of the display device based on the received setting information.Therefore, in the image signal processing system 1000, it is possible torealize the high quality image while preventing the amount of lightentering the eyes of the user from decreasing when the image signal isdisplayed on the display screen.

Meanwhile, although the case in which the image signal processing device200 composing the image signal processing system 1000 processes thereceived transmission signal is described above, this is not limited toabove description. For example, the image signal processing device 200according to the embodiment of the present invention may store contentsdata (data including data corresponding to the image signal and thesetting information) corresponding to the received transmission signalin a storage medium (for example, a storage unit to be described later).In the above-described case, the image signal processing device 200 mayselectively perform the control of the brightness gradient and/or thelight source control of the display device as in the above-describedcase based on the setting information included in the stored contentsdata.

(Image Signal Processing System According to Embodiment of the PresentInvention)

Next, a configuration example of the image signal processing system 1000capable of realizing the above-described high-quality image approachaccording to the embodiment of the present invention is described. FIG.7 is an explanatory diagram for illustrating an overview of the imagesignal processing system 1000 according to the embodiment of the presentinvention.

With reference to FIG. 7, the image signal processing system 1000 hasthe transmitting device 100, image signal processing devices 200A, 200B. . . (hereinafter, sometimes collectively referred to as the “imagesignal processing device 200”) and a receiving device 300.

Herein, although a television receiving set capable of(directly/indirectly) receiving a broadcast wave 500 on which thetransmission signal transmitted by the transmitting device 100 from atelevision tower and the like is put and displaying the image (movingimage/still image) based on the image signal included in the receivedtransmission signal is illustrated in FIG. 7 as the image signalprocessing devices 200A and 200B, this is not limited to the abovedescription.

Although a set top box is illustrated in FIG. 7 as the receiving device300 capable of (directly/indirectly) receiving the broadcast wave 500transmitted by the transmitting device 100 from the television tower andthe like, this is not limited to the above description.

Herein, direct reception of the transmission signal related to thebroadcast wave 500 is intended to mean the reception of the broadcastwave 500 by each device such as the image signal processing device 200and the receiving device 300, for example. Further, indirect receptionof the transmission signal related to the broadcast wave 500 in theimage signal processing device 200 is intended to mean the reception ofthe transmission signal transferred from an external antenna, whichreceives the broadcast wave 500, by the image signal processing device200 or the reception of the transmission signal through the receivingdevice 300, for example. Further, the indirect reception of thetransmission signal related to the broadcast wave 500 in the receivingdevice 300 is intended to mean the reception of the transmission signaltransferred from the external antenna, which receives the broadcast wave500, by the receiving device 300, for example.

The transmitting device 100, the image signal processing device 200A andthe receiving device 300 are connected to one another through a network600 (or directly). Further, the image signal processing device 200B andthe receiving device 300 are connected to each other by a connectioninterface 650. Herein, the term “connect” according to the embodiment ofthe present invention is intended to mean that the devices are in acommunicable state (or put in the communicable state), for example.

Although there is a wired network such as a local area network (LAN) anda wide area network (WAN), a wireless network such as wireless wide areanetwork (WWAN) and wireless metropolitan area network (WMAN) through abase station, or an Internet using a communication protocol such as atransmission control protocol/Internet protocol (TCP/IP), for example,as the network 600, this is not limited to the above description.

Although there is a high-definition multimedia interface (HDMI) as theconnection interface 650, for example, this is not limited to the abovedescription. For example, the connection interface 650 may be auniversal serial bus (USB), an interface using a D terminal and aninterface using an optical digital audio terminal.

Meanwhile, although the example in which the transmitting device 100performs both of the transmission of the image signal through thebroadcast wave 500 and the transmission of the image signal through thenetwork 600 is illustrated in FIG. 7, this is not limited to the abovedescription. The transmitting device 100 according to the embodiment ofthe present invention may transmit the image signal through thebroadcast wave 500 and/or transmit the image signal through the network600.

As illustrated in FIG. 7, the image signal processing device 200 mayreceive the transmission signal transmitted from the transmitting device100 through the receiving device 300 and may receive the transmissionsignal without the receiving device 300.

Hereinafter, a configuration example of each device composing the imagesignal processing system 1000 is described. Further, hereinafter, anexample of a configuration to receive the transmission signal withoutthe receiving device 300 (image signal processing device 200A) and aconfiguration to receive the transmission signal through the receivingdevice 300 (image signal processing device 200B) is described as aconfiguration example of the image signal processing device 200.

[Transmitting Device 100]

FIG. 8 is an explanatory diagram illustrating an example of aconfiguration of the transmitting device 100 according to the embodimentof the present invention. With reference to FIG. 8, the transmittingdevice 100 is provided with a frame format processing unit 102, asetting unit 104, a transmission signal generating unit 106 and atransmitting unit 108.

Further, the transmitting device 100 may be provided with a controller(not illustrated), a read only memory (ROM; not illustrated), a randomaccess memory (RAM; not illustrated), the storage unit (notillustrated), an operating unit, which a user of the transmitting device100 may operate (not illustrated), a display unit to display variousscreens on the display screen (not illustrated) and the like, forexample. The transmitting device 100 connects the above-describedcomponents by a bus as a transmission path of data, for example.

Herein, the controller (not illustrated) is composed of a microprocessing unit (MPU), various processing circuits and the like, forexample, to control an entire transmitting device 100. Further, thecontroller (not illustrated) may serve as the frame format processingunit 102, the setting unit 104 and the transmission signal generatingunit 106, for example.

The ROM (not illustrated) stores control data such as a program and anarithmetic parameter used by the controller (not illustrated). The RAM(not illustrated) temporarily stores the program executed by thecontroller (not illustrated) and the like. Although there is a magneticrecording medium such as a hard disk, and a nonvolatile memory such asan electrically erasable and programmable read only memory (EEPROM), aflash memory, a magnetoresistive random access memory (MRAM), aferroelectric random access memory (FeRAM) and a phase change randomaccess memory (PRAM) as the storage unit (not illustrated), for example,this is not limited to the above description.

Although there is a rotary selector such as a button, a direction keyand a jog dial or combination of them, for example, as the operatingunit (not illustrated), this is not limited to the above description.Although there is the liquid crystal display and the organic EL display,for example, as the display unit (not illustrated), this is not limitedto the above description. Further, the transmitting device 100 may beconnected to an operation input device (keyboard and a mouse, forexample) and a display device (external display, for example) asexternal devices of the transmitting device 100.

The frame format processing unit 102 converts the image signal to betransmitted into a predetermined frame format corresponding to thetransmission signal.

Herein, although there is the image signal obtained by imagingtransferred from an imaging device such as a camera, for example, as theimage signal to be transmitted processed by the frame format processingunit 102, this is not limited to the above description. For example, theimage signal to be transmitted processed by the transmitting device 100according to the embodiment of the present invention may be the imagesignal received from the external device through the network 600 and thelike, and may be the image signal based on the contents data stored inthe storage unit (not illustrated).

Although it is illustrated in FIG. 8 that two image signals are input tothe frame format processing unit 102, this is not limited to the abovedescription. For example, when the image signal input to the frameformat processing unit 102 represents the flat image, any one of theimage signals illustrated in FIG. 8 is input. That is to say, the frameformat processing unit 102 processes both of the image signalcorresponding to the stereoscopic image (when two image signals areinput) and the image signal corresponding to the flat image (when oneimage signal is input). Further, the number of the image signals outputfrom the frame format processing unit 102 corresponds to the number ofthe input image signals.

The setting unit 104 sets set values to be set in the image type settinginformation, the gamma correction setting information and/or thebrightness setting information based on the image signal output from theframe format processing unit 102 (image signal to be transmitted). Then,the setting unit 104 transfers the image type setting information, thegamma correction setting information and/or the brightness settinginformation in which each set value is set to the transmission signalgenerating unit 106.

Meanwhile, in the transmitting device 100 according to the embodiment ofthe present invention, the setting unit 104 may transfer each set valueto the transmission signal generating unit 106 and the transmissionsignal generating unit 106 may generate the image type settinginformation, the gamma correction setting information and/or thebrightness setting information. Hereinafter, a case in which the settingunit 104 generates the image type setting information, the gammacorrection setting information and/or the brightness setting informationto transfer to the transmission signal generating unit 106 is describedas an example.

Herein, although the setting unit 104 sets both of or any one of the setvalue to be set in the gamma correction setting information and the setvalue to be set in the brightness setting information, for example, inaddition to the set value to be set in the image type settinginformation, this is not limited to the above description. For example,it is possible that the setting unit 104 does not perform the processrelated to the setting of the set values to be set in the gammacorrection setting information and the brightness setting informationbased on an operation signal corresponding to the user operationtransferred from the operating unit (not illustrated) and informationdefining not to perform the process included in the image signal.

Although the setting unit 104 sets the set value corresponding to theinformation defined in advance out of the set values to be set in thegamma correction setting information and the brightness settinginformation, for example, this is not limited to the above description.For example, the setting unit 104 may selectively switch the informationin which the set value is set based on the operation signal according tothe user operation transferred from the operating unit (notillustrated).

Hereinafter, a case in which the setting unit 104 sets the set values tobe set in the image type setting information, the gamma correctionsetting information and the brightness setting information is describedas an example.

[Example of Setting Process in Setting Unit 104]

FIG. 9 is a flowchart illustrating an example of a setting process inthe setting unit 104 of the transmitting device 100 according to theembodiment of the present invention. Hereinafter, it is described on theassumption that the setting process illustrated in FIG. 9 is performedby the transmitting device 100.

The transmitting device 100 judges whether the image signal to betransmitted represents the stereoscopic image (S100). Herein, althoughthe transmitting device 100 judges that the image signal to betransmitted represents the stereoscopic image when processing aplurality of image signals, for example, this is not limited to theabove description.

When it is judged that the image signal to be transmitted represents thestereoscopic image in step S100, the transmitting device 100 sets theset value of the image type setting information to the stereoscopicimage (S102). Further, when it is not judged that the image signal to betransmitted represents the stereoscopic image in step S100, thetransmitting device 100 sets the set value of the image type settinginformation to the flat image (S104).

FIG. 10 is an explanatory diagram illustrating an example of the imagetype setting information generated by the transmitting device 100according to the embodiment of the present invention.

When it is judged that the image signal to be transmitted represents thestereoscopic image in step S100, the transmitting device 100 sets“3D_flag” illustrated in FIG. 10, which is a flag indicating whether itis the stereoscopic image, to a state indicating the stereoscopic imagein step S102. Further, when it is not judged that the image signal to betransmitted represents the stereoscopic image in step S100, thetransmitting device 100 sets “3D_flag” illustrated in FIG. 10 to a stateindicating the flat image (state not indicating the stereoscopic image)in step S104. Herein, although the transmitting device 100 sets“3D_flag” illustrated in FIG. 10 to “1” and “0” when the image signalrepresents the stereoscopic image and the flat image, respectively, forexample, this is not limited to the above description.

Further, when it is judged that the image signal to be transmittedrepresents the stereoscopic image in step S100, the transmitting device100 sets the set values of various pieces of information related to theimage signal to be set in the image type setting information based onthe image signal to be transmitted and the contents of the processperformed in the transmission signal generating unit 106, for example.

Herein, although there is a flag indicating whether it is a frame or afield (“Frame_flag” in FIG. 10), a flag indicating a format of thestereoscopic image (“3D_video_format” in FIG. 10) and a flag indicatingwhether a current image signal is a right-eye image signal or a left-eyeimage signal (“Current_image_is_L” in FIG. 10), for example, as theinformation set by the transmitting device 100, this is not limited tothe above description. For example, the transmitting device 100 may setthe various pieces of information related to the process of thestereoscopic image in the image signal processing device 200, whichreceives the image type setting information, in addition to flags“3D_pair_Image”, “Lefthand_side_is_L” and “Top_is_L” illustrated in FIG.10.

Further, the image signal processing device 200, which receives thesetting information including the image type setting informationillustrated in FIG. 10, may uniquely judge whether the image signal tobe processed represents the stereoscopic image based on “3D_flag” set inthe image type setting information. Therefore, when it is judged thatthe image signal to be processed represents the stereoscopic image, theimage signal processing device 200 may selectively perform the processto display the stereoscopic image for the image signal based on thevarious pieces of information set in the image type setting information.

Meanwhile, it goes without saying that the image type settinginformation according to the embodiment of the present invention is notlimited to the example illustrated in FIG. 10.

An example of the setting process in the setting unit 104 of thetransmitting device 100 is described with reference to FIG. 9 again.When the set value for the image type setting information is set in stepS102 or the step S104, the transmitting device 100 derives a brightnessaverage for each divided area based on the image signal (S106).

When the brightness average value for each divided area is derived instep S106, statistics on the brightness average values of the dividedareas of the entire display screen are obtained (S108). Herein, althoughfrequency distribution of the brightness average values of the dividedareas is derived as statistical processing in step S108, for example,this is not limited to the above description.

When the statistics on the brightness average values of the dividedareas of the entire display screen are obtained in step S108, thetransmitting device 100 judges whether “number of divided areas of whichbrightness average value is not larger than predetermined value<firstthreshold” (S110). Herein, although values defined in advance may beused as the predetermined value related to the brightness average value,the first threshold and a second threshold to be described later (firstthreshold>second threshold), this is not limited to the abovedescription. For example, the above-described values may beappropriately set based on the operation signal corresponding to theuser operation transferred from the operating unit (not illustrated).

When it is judged that “number of divided areas of which brightnessaverage value is not larger than predetermined value<first threshold” instep S110, the transmitting device 100 assumes that the imagerepresented by the image signal is sufficiently bright as a whole andsets first set values in the gamma correction setting information andthe brightness setting information (S112).

Herein, as the first set value according to the embodiment of thepresent invention, there is the set value for not allowing the imagesignal processing device 200 to perform the control of the brightnessgradient and the light source control of the display device based on thesetting information, for example. More specifically, the transmittingdevice 100 sets the gamma correction value to be set in the gammacorrection setting information to 2.2, for example. Further, thetransmitting device 100 sets the information of the average brightnesslevel to be set in the brightness setting information to a valuecorresponding to the brightness average value derived in step S106, forexample. Meanwhile, the value set as the first set value by thetransmitting device 100 and a type of the set value are not limited tothe above description. For example, the transmitting device 100 may setthe set values to be set in the various pieces of information composingthe gamma correction setting information illustrated in FIG. 5 and thevarious pieces of information composing the brightness settinginformation illustrated in FIG. 6.

Further, in step S110, when it is not judged that “number of dividedareas of which brightness average value is not larger than predeterminedvalue<first threshold”, the transmitting device 100 judges whether“number of divided areas of which brightness average value is not largerthan predetermined value≧second threshold” (S114).

At the step S114, when it is judged that “number of divided areas ofwhich brightness average value is not larger than predeterminedvalue≧second threshold”, the transmitting device 100 assumes that thereis a dark portion in the image represented by the image signal and setssecond set values in the gamma correction setting information and thebrightness setting information (S116).

Herein, as the second set value according to the embodiment of thepresent invention, there is the set value for not allowing the imagesignal processing device 200 to perform the control of the brightnessgradient based on the setting information but allowing the same toperform the light source control of the display device, for example.More specifically, the transmitting device 100 sets the gamma correctionvalue to be set in the gamma correction setting information to 2.2, forexample. Further, the transmitting device 100 sets the information ofthe average brightness level to be set in the brightness settinginformation, for example, to a value higher than the value correspondingto the brightness average value derived in step S106. Meanwhile, thevalue set as the second set value by the transmitting device 100 and atype of the set value are not limited to the above description. Forexample, the transmitting device 100 may set the set value for allowingthe image signal processing device 200 to perform the control of thebrightness gradient based on the setting information and not allowingthe same to perform the light source control of the display device asthe second set value.

Further, when it is not judged that “number of divided areas of whichbrightness average value is not larger than predetermined value≧secondthreshold” in step S114, the transmitting device 100 assumes that thereis a larger dark portion in the image represented by the image signaland sets third set values in the gamma correction setting informationand the brightness setting information (S118).

Herein, as the third set value according to the embodiment of thepresent invention, there is a set value for allowing the image signalprocessing device 200 to perform the control of the brightness gradientand the light source control of the display device based on the settinginformation, for example. More specifically, the transmitting device 100sets the gamma correction value to be set in the gamma correctionsetting information to a value larger than 2.2, for example. Further,the transmitting device 100 sets the information of the averagebrightness level to be set in the brightness setting information to avalue higher than the value corresponding to the brightness averagevalue derived in step S106, for example. Meanwhile, the value set by thetransmitting device 100 as the third set value and a type of the setvalue are not limited to the above description.

The transmitting device 100 may set the set values to be set in theimage type setting information, the gamma correction setting informationand the brightness setting information by performing the processillustrated in FIG. 9, for example. Meanwhile, the setting process inthe setting unit 104 of the transmitting device 100 according to theembodiment of the present invention is not limited to the exampleillustrated in FIG. 9. For example, although the configuration in whichthe transmitting device 100 performs the setting process using the twopredetermined thresholds is illustrated in FIG. 9, this is not limitedto the above description, and the transmitting device 100 according tothe embodiment of the present invention may perform the setting processby setting the set values of “number of thresholds+1 pattern” using oneor two or more predetermined threshold.

An example of the configuration of the transmitting device 100 isdescribed with reference to FIG. 8 again. The transmission signalgenerating unit 106 generates the transmission signal based on the imagesignal transferred from the frame format unit 102, the image typesetting information, the gamma correction setting information and thebrightness setting information transferred from the setting unit 104.The transmission signal generating unit 106 then transfers the generatedtransmission signal to the transmitting unit 108.

Herein, although the transmission signal generating unit 106 is composedof an encoder 110 for encoding the image signal based on a predeterminedrule and a multiplexer 112 for outputting the transmission signal basedon the image signal and the setting information encoded by the encoder110, this is not limited to the above description.

The transmitting unit 108 transmits the transmission signal transferredfrom the transmission signal generating unit 106.

Herein, although the configuration in which the transmitting unit 108 isprovided with a first transmitting unit 114 for transmitting thetransmission signal through the broadcast wave 500 and a secondtransmitting unit 116 for transmitting the transmission signal throughthe network 600 is illustrated in FIG. 8, this is not limited to theabove description. For example, the transmitting device according to theembodiment of the present invention may be provided with any one of thefirst transmitting unit 114 and the second transmitting unit 116.

Although the first transmitting unit 114 is composed of a modulator 118and a radio frequency (RF) transmitter 120, for example, this is notlimited to the above description. Although the second transmitting unit116 is composed of a protocol processing unit 122 and an interface 124for connecting to the network 600, for example, this is not limited tothe above description.

The transmitting device 100 may generate the setting information foreach predetermined unit of the image signal based on the image signal tobe transmitted to transmit the image signal and the setting informationwith the configuration illustrated in FIG. 8, for example. Meanwhile, itgoes without saying that the configuration of the transmitting deviceaccording to the embodiment of the present invention is not limited tothe configuration illustrated in FIG. 8.

[Image Signal Processing Device 200]

Next, a configuration of the image signal processing device 200according to the embodiment of the present invention is described.

[1] First Configuration Example Configuration Example Corresponding toImage Signal Processing Device 200A

FIG. 11 is an explanatory diagram illustrating a first example of theconfiguration of the image signal processing device 200 according to theembodiment of the present invention. Herein, FIG. 11 illustrates anexample of a configuration of the image signal processing device 200Afor receiving the transmission signal transmitted from the transmittingdevice 100 without the receiving device 300 as the configuration relatedto the first example of the image signal processing device 200.

Although the configuration in which the image signal processing device200A has both of a control function of the brightness gradient based onthe received setting information and a light source control function ofthe display device based on the setting information illustrated in FIG.11, this is not limited to the above description. As described above,the image signal processing device according to the embodiment of thepresent invention may be configured to have any one of the controlfunction of the brightness gradient based on the received settinginformation and the light source control function of the display devicebased on the setting information.

The image signal processing device 200A is provided with a storage unit202, a receiving unit 204, a first image signal processing unit 206, agamma correcting unit 208, a brightness adjusting unit 210, a secondimage signal processing unit 212 (stereoscopic image processing unit)and a display unit 214.

Further, the image signal processing device 200A may be provided with acontroller (not illustrated), the ROM (not illustrated), the RAM (notillustrated), an operating unit (not illustrated), which may be operatedby the user of the image signal processing device 200A, an externalcommunicating unit (not illustrated) for communicating with the externaldevice for allowing the user to watch the stereoscopic image, such asliquid crystal shutter glasses and the like. The image signal processingdevice 200A connects the above-described components by the bus as thetransmission path of the data, for example.

Herein the controller (not illustrated) is composed of the MPU, thevarious processing circuits and the like, for example, to control anentire image signal processing device 200A. Further, the controller (notillustrated) may serve as the first image signal processing unit 206,the gamma correcting unit 208, the brightness adjusting unit 210 and thesecond image signal processing unit 212, for example.

The ROM (not illustrated) stores the control data such as the programand the arithmetic parameter used by the controller (not illustrated).The RAM (not illustrated) temporarily stores the program and the likeexecuted by the controller (not illustrated). Although there is therotary selector such as the button, the direction key and the jog dialor combination of them, for example, as the operating unit (notillustrated), this is not limited to the above description. Althoughthere is an IEEE802.15.1 port and a transmitting and receiving circuit(wireless communication), an IEEE802.11b port and the transmitting andreceiving circuit (wireless communication) and the like, for example, asthe external communicating unit (not illustrated), this is not limitedto the above description.

The storage unit 202 is storing means provided in the image signalprocessing device 200A. Herein, although there is the magnetic recordingmedium such as the hard disk and the nonvolatile memory such as theflash memory, for example, as the storage unit 202, this is not limitedto the above description.

The storage unit 202 stores various data such as the contents datacorresponding to the received transmission signal, the contents dataindependent of the received transmission signal, process executinginformation and various applications, for example. Herein, although theexample in which contents data 240 corresponding to the receivedtransmission signal and process executing information 242 are stored inthe storage unit 202 is illustrated in FIG. 11, this is not limited tothe above description. For example, the image signal processing device200 according to the embodiment of the present invention may store theprocess executing information in a storage medium separate from thestorage unit 202 such as the above-described ROM, for example.

Herein, the process executing information according to the embodiment ofthe present invention is information for selectively executing thecontrol of the brightness gradient based on the setting information, thelight source control of the display device based on the settinginformation and the process to display the stereoscopic image accordingto the embodiment of the present invention, for example. When it isdefined in the process executing information to limit execution of thecontrol and the like, the image signal processing device 200 accordingto the embodiment of the present invention does not execute the controland the like. As described above, the image signal processing device 200according to the embodiment of the present invention stores the processexecuting information, so that, the image signal processing device 200may selectively activate the function of the image signal processingdevice 200 without depending on the setting information included in thereceived transmission signal, for example. Further, the image signalprocessing device 200 stores the process executing information asdescribed above, so that, the image signal processing device 200 mayperform the process corresponding to the function of the device itselfwithout depending on the setting information also when this does nothave the control function corresponding to the received settinginformation, for example.

The receiving unit 204 receives the transmission signal and transfersthe image signal and the setting information included in thetransmission signal to the corresponding components. More specifically,the receiving unit 204 transfers the image signal to the first imagesignal processing unit 206 and transfers the image type settinginformation to the second image signal processing unit 212. Further, thereceiving unit 204 transfers the gamma correction setting information tothe gamma correcting unit 208 and transfers the brightness settinginformation to the brightness controller 210.

[Configuration Example of Receiving Unit 204]

FIG. 12 is an explanatory diagram illustrating an example of aconfiguration of the receiving unit 204 provided in the image signalprocessing device 200 according to the embodiment of the presentinvention. Herein, FIG. 12 illustrates an example of a configuration inwhich the image signal processing device 200 has a function to receivethe transmission signal through the broadcast wave 500, a function toreceive the transmission signal through the network 600 and a functionto process the contents data stored in the storage unit 202.

The receiving unit 204 is provided with a tuner 220, a demodulator 222,an interface 224, a protocol processing unit 226, a switching unit 228,a demultiplexer 230 and a decoder 232.

The tuner 220 and the demodulator 222 serve to receive the transmissionsignal through the broadcast wave 500. Further, the interface 224 andthe protocol processing unit 226 serve to receive the transmissionsignal through the network 600.

The transmission signal transferred from the demodulator 222, thetransmission signal transferred from the protocol processing unit 226and the contents data stored in the storage unit 202 are input to theswitching unit 228, and this selectively transfers any one of them tothe demultiplexer 230. Hereinafter, a case in which the switching unit228 transfers the transmission signal to the demultiplexer 230 isdescribed as an example.

Herein, although the switching unit 228 switches the transmission signaland the like to be output based on the operation signal corresponding tothe user operation transferred from the operating unit (notillustrated), for example, this is not limited to the above description.

The demultiplexer 230 divides the image signal and the settinginformation (image type setting information, gamma correction settinginformation and brightness setting information) based on thetransmission signal transferred from the switching unit 228, andtransfers the image signal and the setting information to the decoder232. Herein, when the setting information is not included in thetransmission signal and the contents data, the demultiplexer 230 doesnot transfer the setting information to the decoder 232.

The decoder 232 decodes the image signal and the setting informationtransferred from the demultiplexer 230 to transfer the decoded imagesignal, image type setting information, gamma correction settinginformation and brightness setting information to the correspondingcomponents.

The receiving unit 204 may transfer the image signal and the settinginformation included in the transmission signal to the correspondingcomponents with the configuration illustrated in FIG. 12, for example.Meanwhile, it goes without saying that the configuration of thereceiving unit provided in the image signal processing device 200according to the embodiment of the present invention is not limited tothe configuration illustrated in FIG. 12.

The first configuration example of the image signal processing device200 is described with reference to FIG. 11 again. The first image signalprocessing unit 206 processes the image signal transferred from thereceiving unit 206 and transfers the processed image signal to the gammacorrecting unit 208.

Herein, although there is a scaling process, an interlace/progressiveconversion process and the like, for example, as the process in thefirst image signal processing unit 206, this is not limited to the abovedescription.

The gamma correcting unit 208 serves to control the brightness gradientbased on the setting information. More specifically, the gammacorrecting unit 208 performs the gamma correction for the image signalbased on the gamma correction setting information transferred from thereceiving unit 204 and the image signal transferred from the first imagesignal processing unit 206.

Further, the gamma correcting unit 208 may selectively perform thecontrol of the brightness gradient based on the setting informationbased on the process executing information.

The brightness controller 210 serves to perform the light source controlof the display device based on the setting information. Morespecifically, the brightness controller 210 generates the brightnesscontrol signal based on the image signal (not illustrated in FIG. 11)transferred from the first image signal processing unit 206 and thebrightness setting information transferred from the receiving unit 204and transfers the brightness control signal to the display unit 214, forexample.

Further, the brightness controller 210 may selectively perform the lightsource control of the display device based on the setting informationbased on the process executing information.

The second image signal processing unit 212 selectively performs theprocess to display the stereoscopic image for the image signaltransferred from the gamma correcting unit 208 based on the image typesetting information transferred from the receiving unit 204. Morespecifically, the second image signal processing unit 212 judges whetherthe image signal represents the stereoscopic image based on “3D_flag” ofthe image type setting information illustrated in FIG. 10 and performsthe process to display the stereoscopic image when the signal representsthe stereoscopic image, for example.

Herein, although there is a deformatting process corresponding to“3D_video_format” illustrated in FIG. 10 and a stereoscopic conversionprocess in a stereoscopic rendering process (process related to displaymultiplexing of the right-eye image signal and the left-eye imagesignal), for example, as the process in the second image signalprocessing unit 212, this is not limited to the above description.

Further, when the second image signal processing unit 212 performs theprocess to display the stereoscopic image, for example, this maytransmit the information related to the process to the external devicefor allowing the user to watch the stereoscopic image such as the liquidcrystal shutter glasses through the external communicating unit (notillustrated). In this manner, the image signal processing device 200Amay allow the user to watch the stereoscopic image corresponding to theimage signal in cooperation with the external device for allowing theuser to watch the stereoscopic image such as the liquid crystal shutterglasses. Meanwhile, it goes without saying that a method of cooperatingwith the external device for allowing the user to watch the stereoscopicimage such as the liquid crystal shutter glasses in the image signalprocessing device 200 according to the embodiment of the presentinvention is not limited to the above description.

Further, the second image signal processing unit 212 may selectivelyperform the process based on the image type setting information based onthe process executing information.

The display unit 214 displays the image corresponding to the imagesignal transferred from the second image signal processing unit 212 onthe display screen. Further, the display unit 214 adjusts the brightnessfor each part of the display screen according to the brightness controlsignal transferred from the brightness controller 210.

Herein, although there is the display device having the light sourcecapable of emitting light for each area corresponding to each pixel or aplurality of pixels such as the liquid crystal display, for example, asthe display unit 214, this is not limited to the above description. Forexample, the display unit 214 may be the self-emitting type displaydevice without the separate light source such as the organic EL display.When the display unit 214 is configured to have the separate lightsource, the light emission of the light source is controlled accordingto the brightness control signal, and when the display unit 214 isconfigured to be the self-emitting type without the separate lightsource, the light emission of a light emitting device is controlledaccording to the brightness control signal, for example.

The image signal processing device 200A corresponding to the firstconfiguration example of the image signal processing device 200according to the embodiment of the present invention may process thereceived image signal and selectively perform the control of thebrightness gradient and the light source control of the display devicebased on the received setting information with the configurationillustrated in FIG. 11, for example. Meanwhile, it goes without sayingthat the first configuration example of the image signal processingdevice 200 according to the embodiment of the present invention is notlimited to the configuration illustrated in FIG. 11.

[2] Second Configuration Example Configuration Example Corresponding toImage Signal Processing Device 200B

FIG. 13 is an explanatory diagram illustrating a second example of theconfiguration of the image signal processing device 200 according to theembodiment of the present invention. Herein, FIG. 13 illustrates anexample of the configuration of the image signal processing device 200B,which receives the transmission signal transmitted from the transmittingdevice 100 through the receiving device 300, as the configurationaccording to the second example of the image signal processing device200. Further, FIG. 13 illustrates the receiving device 300 together.

With reference to FIG. 13, the image signal processing device 200B isprovided with a communicating unit 250 for receiving the transmissionsignal transmitted from the receiving device 300, the gamma correctingunit 208, the brightness adjusting unit 210, the second image signalprocessing unit 212 (stereoscopic image processing unit) and the displayunit 214.

Further, the image signal processing device 200B may be provided withthe controller (not illustrated), the ROM (not illustrated), the RAM(not illustrated), the storage unit (not illustrated), the operatingunit (not illustrated), the external communicating unit (notillustrated) and the like as the image signal processing device 200Aaccording to the first configuration example.

The communicating unit 250 receives the transmission signal transmittedfrom the receiving device 300 through the connection interface 650.Then, the communicating unit 250 transfers the image signal and thesetting information (image type setting information, gamma correctionsetting information and brightness setting information) to thecorresponding components based on the received transmission signal.

More specifically, the communicating unit 250 transfers the image signaland the gamma correction setting information to the gamma correctingunit 208 and transfers the image type setting information to the secondimage signal processing unit 212. Further, the communicating unit 250transfers the brightness setting information to the brightnesscontroller 210. That is to say, the communicating unit 250 provided inthe image signal processing device 200B according to the secondconfiguration example serves to receive the transmission signal andtransfer the image signal and the setting information included in thetransmission signal to the corresponding components (serves as thereceiving unit in the image signal processing device 200) as thereceiving unit 204 provided in the image signal processing device 200Aaccording to the second configuration example.

Herein, when the connection interface 650 is the HDMI, the receivingdevice 300 (communicating unit provided in the above-described receivingdevice 300) serves as a HDMI source and the communicating unit 250serves as a HDMI sink.

<Configuration Example of Receiving Device 300>

Herein, a configuration of the receiving device 300 for transmitting thetransmission signal through the connection interface 650 is described.FIG. 14 is an explanatory diagram illustrating an example of theconfiguration of the receiving device 300 according to the embodiment ofthe present invention. Herein, FIG. 14 illustrates the image signalprocessing device 200B together.

The receiving device 300 is provided with the receiving unit 302, theimage signal processing unit 304 and the communicating unit 306.

Further, the receiving device 300 may be provided with a controller (notillustrated) composed of the MPU and the like for controlling an entirereceiving device 300, the ROM (not illustrated), the RAM (notillustrated), a display unit (not illustrated) for displaying a stateand the like of the receiving device 300 on the display screen.

Herein, the ROM (not illustrated) stores the control data such as theprogram and the arithmetic parameter used by the controller (notillustrated). The RAM (not illustrated) temporarily stores the programand the like executed by the controller (not illustrated). Althoughthere is the liquid crystal display and the like, for example, as thedisplay unit (not illustrated), this is not limited to the abovedescription.

The receiving unit 302 receives the transmission signal and transfersthe image signal and the setting information included in thetransmission signal to the corresponding components. More specifically,the receiving unit 302 transfers the image signal to the image signalprocessing unit 304 and transfers the setting information to thecommunicating unit 306.

Herein, the receiving unit 302 may have the configuration similar tothat of the receiving unit 204 provided in the image signal processingdevice 200A illustrated in FIG. 12, for example, this is not limited tothe above description.

The image signal processing unit 304 processes the image signaltransferred from the receiving unit 302 and transfers the processedimage signal to the communicating unit 306.

Herein, although there is the process similar to that of the first imagesignal processing unit 206 provided in the image signal processingdevice 200A illustrated in FIG. 11, for example, as the process in theimage signal processing unit 304, this is not limited to the abovedescription.

The communicating unit 306 transmits the transmission signalcorresponding to the received transmission signal to the image signalprocessing device 200B based on the setting information transferred fromthe receiving unit 302 and the image signal transferred from the imagesignal processing unit 304.

FIGS. 15 and 16 are explanatory diagrams illustrating an example of thetransmission signal transmitted by the receiving device 300 according tothe embodiment of the present invention. Herein, FIG. 15 illustrates anexample of a case in which the receiving unit 302 of the receivingdevice 300 transmits the transmission signal using the HDMI version 1.4.Further, FIG. 16 illustrates an example of a case in which the receivingunit 302 of the receiving device 300 transmits the transmission signalusing the HDMI version 1.3. Further, each reference 11 to 13 in FIGS. 15and 16 represents InfoFrame (including Vendor Specific, AVI InfoFrameand the like) capable of transmitting the setting information.

As illustrated in FIG. 15, when transmitting the transmission signalusing the HDMI version 1.4, the receiving unit 302 arranges the left-eyeimage signal (corresponding to L in FIG. 15) and the right-eye imagesignal (corresponding to R in FIG. 15) in Vfreq in a frame unit. In theabove-described case, the receiving unit 302 may transfer the imagesignal by SideBySide, Top&Bottom and Frame Sequential by extending aformat definition of the HDMI.

Further, as illustrated in FIG. 16, when transmitting the transmissionsignal by using the HDMI version 1.3, the receiving unit 302 maytransmit the left-eye image signal (corresponding to L in FIG. 15) orthe right-eye image signal (corresponding to R in FIG. 15) and thesetting information for each Vfreq.

Meanwhile, it goes without saying that the transmission signaltransmitted and received through the connection interface 650 betweenthe receiving device 300 and the image signal processing device 200Baccording to the embodiment of the present invention is not limited tothe transmission signal illustrated in FIGS. 15 and 16.

The receiving device 300 may transmit the transmission signalcorresponding to the received transmission signal to the image signalprocessing device 200B through the connection interface 650 with theconfiguration illustrated in FIG. 14, for example. Meanwhile, theconfiguration of the receiving device 300 according to the embodiment ofthe present invention is not limited to the configuration illustrated inFIG. 14.

The second configuration example of the image signal processing device200 is described with reference to FIG. 13 again. The gamma correctingunit 208, the brightness adjusting unit 210, the second image signalprocessing unit 212 (stereoscopic image processing unit) and the displayunit 214 have the functions and configurations similar to those of thegamma correcting unit 208, the brightness adjusting unit 210, the secondimage signal processing unit 212 (stereoscopic image processing unit)and the display unit 214 illustrated in FIG. 11, respectively. That isto say, the image signal processing device 200B may selectively performthe control of the brightness gradient based on the setting informationin the gamma correcting unit 208 and may selectively perform the lightsource control of the display device based on the setting information inthe brightness adjusting unit 210.

As illustrated in FIG. 13, the image signal processing device 200B isdifferent from the image signal processing device 200A according to thefirst configuration example illustrated in FIG. 11 in that this is notprovided with the receiving unit 204 and the first image signalprocessing unit 206 but is provided with the communicating unit 250.However, the image signal processing device 200B may selectively performthe control of the brightness gradient based on the setting informationand the light source control of the display device based on the settinginformation as the image signal processing device 200A according to thefirst configuration example illustrated in FIG. 11.

Therefore, the image signal processing device 200 may process thereceived image signal and selectively perform the control of thebrightness gradient and the light source control of the display devicebased on the received setting information as the image signal processingdevice 200A according to the first configuration example illustrated inFIG. 11.

[3] Another Configuration Example

The configuration of receiving the transmission signal transmitted fromthe transmitting device 100 without the receiving device 300 (firstconfiguration example) and the configuration of receiving thetransmission signal through the receiving device 300 (secondconfiguration example) are described above as the configuration examplesof the image signal processing device 200 according to the embodiment ofthe present invention. However, the configuration of the image signalprocessing device 200 according to the embodiment of the presentinvention is not limited to the above-described first and secondconfiguration examples.

For example, the image signal processing device 200 according to theembodiment of the present invention may have the configuration obtainedby combining the configuration according to the first configurationexample illustrated in FIG. 11 and the configuration according to thesecond configuration example illustrated in FIG. 13. With theabove-described configuration also, the image signal processing device200 according to the embodiment of the present invention may process thereceived image signal and selectively perform the control of thebrightness gradient and the light source control of the display devicebased on the received setting information as in the above-describedfirst and second configuration examples.

As described above, the image signal processing system 1000 according tothe embodiment of the present invention has the transmitting device 100,the image signal processing device 200 and the receiving device 300. Thetransmitting device 100 transmits the image signal and the settinginformation for each predetermined unit. The image signal processingdevice 200 processes the image signal received (through the receivingdevice 300/without the receiving device 300) and selectively performsthe control of the brightness gradient and/or the light source controlof the display device based on the received setting information.Therefore, in the image signal processing system 1000, it becomespossible to prevent the amount of light entering the eyes of the userfrom decreasing when the image processed by the image signal processingdevice 200 is displayed on the display screen of the display device.

Further, in the image signal processing system 1000, the image signalprocessing device 200 performs the control of the brightness gradientand/or the light source control of the display device based on thesetting information transmitted by the transmitting device 100. That isto say, in the image signal processing device 200 according to theembodiment of the present invention, the control of the brightnessgradient and/or the light source control of the display device is notfreely performed based on the received image signal as in the case ofusing the method of preventing the amount of light entering the eyes ofthe user from decreasing. Therefore, in the image signal processingsystem 1000, possibility that the image displayed on the display screenand watched by the user does not sufficiently reflect the intention ofthe contents author side may be further reduced, so that the higherquality image may be realized.

Therefore, with the transmitting device 100 and the image signalprocessing device 200, the image signal processing system capable ofrealizing the high quality image while preventing the amount of lightentering the eyes of the user from decreasing when the image signal isdisplayed on the display screen is realized.

Further, in the image signal processing system 1000, the transmittingdevice 100 selectively transmits the setting information correspondingto the type (flat image/stereoscopic image) of the image of the imagesignal to be transmitted and the image signal processing device 200performs the process based on the setting information. Therefore, theuser who watches the image corresponding to the image signal processedby the image signal processing device 200 may watch the image with thesame brightness level when the flat image is displayed and when thestereoscopic image is displayed on the display screen.

Further, in the image signal processing system 1000, the transmittingdevice 100 sets the set value to be set in the setting information basedon the brightness average value for each divided area as illustrated inFIG. 9, for example, and the image signal processing device 200 performsthe process based on the setting information. Therefore, in the imagesignal processing system 1000, there is compatibility in the displaylevel of the image displayed on the display screen when each control inthe image signal processing device 200 is necessary and when the controlis not necessary.

Although the transmitting device 100 is described above as the componentcomposing the image signal processing system 1000 according to theembodiment of the present invention, the embodiment of the presentinvention is not limited to this. The embodiment of the presentinvention may be applied to various devices such as a computer such as aserver and a personal computer (PC), for example.

Although the image signal processing device 200 is described as thecomponent composing the image signal processing system 1000 according tothe embodiment of the present invention, the embodiment of the presentinvention is not limited to this. The embodiment of the presentinvention may be applied to various devices such as the computer such asPC, a portable communicating device such as a cell phone and a personalhandyphone system (PHS), video/audio reproducing device (or video/musicrecording reproducing device), a portable game machine and thetelevision receiving set, for example.

Although the receiving device 300 is described as components composingthe image signal processing system 1000 according to the embodiment ofthe present invention, the embodiment of the present invention is notlimited to this. The embodiment of the present invention may be appliedto various devices such as the set top box, the computer such as the PCand the television receiving set, for example.

(Program According to Embodiment of the Present Invention)

It is possible to generate the setting information for eachpredetermined unit of the image signal based on the image signal to betransmitted and transmit the image signal and the setting information bythe program for causing the computer to serve as the transmitting deviceaccording to the embodiment of the present invention. Therefore, by theprogram for causing the computer to serve as the transmitting deviceaccording to the embodiment of the present invention, the image signalprocessing system capable of realizing the high quality image whilepreventing the amount of light entering the eyes of the user fromdecreasing when the image signal is displayed on the display screen maybe realized.

Further, it is possible to process the received image signal andselectively perform the control of the brightness gradient and the lightsource control of the display device based on the received settinginformation by the program for causing the computer to serve as theimage signal processing device according to the embodiment of thepresent invention. Therefore, by the program for causing the computer toserve as the image signal processing device according to the embodimentof the present invention, the image signal processing system capable ofrealizing the high quality image while preventing the amount of lightentering the eyes of the user from decreasing when the image signal isdisplayed on the display screen may be realized.

Further, it is possible to transfer the transmission signalcorresponding to the transmission signal transmitted from thetransmitting device to the image signal processing device by the programfor causing the computer to serve as the receiving device according tothe embodiment of the present invention. Therefore, by the program forcausing the computer to serve as the image signal processing deviceaccording to the embodiment of the present invention, the image signalprocessing system capable of realizing the high quality image whilepreventing the amount of light entering the eyes of the user fromdecreasing when the image signal is displayed on the display screen maybe realized.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

For example, although it is described above that the program (computerprogram) for causing the computer to serve as the transmitting device,the image signal processing device and the receiving device according tothe embodiment of the present invention is provided, the embodiment ofthe present invention may further provide the storage medium in whichthe above-described program is stored.

The above-described configuration describes an example of the embodimentof the present invention and is naturally within the scope of thetechnical field of the present invention.

The invention claimed is:
 1. An image signal processing device,comprising: a receiving unit for receiving an image signal and settinginformation for each predetermined unit of the image signal includinggamma correction setting information to define a gamma correction amountfor the image signal; a gamma correcting unit for performing gammacorrection for the image signal based on the gamma correction settinginformation included in the setting information received by thereceiving unit; and an image processing unit for selectively performinga process to display the image for the image signal corrected by thegamma correcting unit based on the image type setting informationincluded in the setting information received by the receiving unit,wherein the gamma correction setting information is determined bycomputing a brightness average value for each of a plurality of dividedareas of the image signal, determining a number of divided areas forwhich the brightness average value is not larger than a predeterminedvalue, comparing the number of divided areas for which the brightnessaverage value is not larger than a predetermined value to a threshold,and setting the gamma correction setting information according towhether or not the number of divided areas for which the brightnessaverage value is not larger than a predetermined value is less than thethreshold.
 2. The image signal processing device according to claim 1,wherein the gamma correcting unit selectively performs the gammacorrection based on the gamma correction setting information based onprocess executing information related to execution of a process beingstored.
 3. The image signal processing device according to claim 1,further comprising: a display unit for displaying an image correspondingto the image signal output from the image processing unit on a displayscreen and is capable of adjusting brightness for each part of thedisplay screen; and a brightness controller for transferring abrightness control signal for controlling the brightness of the eachpart of the display screen to the display unit, wherein the settinginformation further includes brightness setting information to definethe brightness of each part of the display screen, and the brightnesscontroller transfers the brightness control signal based on thebrightness setting information included in the setting informationreceived by the receiving unit to the display unit.
 4. A transmittingdevice, comprising: a setting unit for setting gamma correction settinginformation to define a gamma correction amount for the image signal tobe transmitted and/or brightness setting information to definebrightness of each part of a display screen for each predetermined unitof the image signal to be transmitted based on the image signal to betransmitted; a transmission signal generating unit for generating atransmission signal including the image signal to be transmitted andsetting information for each predetermined unit of the image signal tobe transmitted including the image type setting information, the gammacorrection setting information and/or the brightness setting informationbased on the image signal to be transmitted and the set values for eachpredetermined unit of the image signal to be transmitted set by thesetting unit; and a transmitting unit for transmitting the transmissionsignal generated by the transmission signal generating unit, wherein thegamma correction setting information is determined by computing abrightness average value for each of a plurality of divided areas of theimage signal, determining a number of divided areas for which thebrightness average value is not larger than a predetermined value,comparing the number of divided areas for which the brightness averagevalue is not larger than a predetermined value to a threshold, andsetting the gamma correction setting information according to whether ornot the number of divided areas for which the brightness average valueis not larger than a predetermined value is less than the threshold. 5.The transmitting device according to claim 4, wherein the setting unitderives degree distribution of brightness average values for eachdivided area and sets the set values based on the derived degreedistribution and one or two or more predetermined threshold.
 6. An imagesignal processing method, comprising the steps of: receiving an imagesignal and setting information for each predetermined unit in the imagesignal including gamma correction setting information to define a gammacorrection amount for the image signal; performing gamma correction forthe image signal based on the gamma correction setting informationincluded in the setting information received in the step of receiving;and selectively performing a process to display the image for the imagesignal corrected in the step of performing the gamma correction based onthe image type setting information included in the setting informationreceived in the step of receiving, wherein the gamma correction settinginformation is determined by computing a brightness average value foreach of a plurality of divided areas of the image signal, determining anumber of divided areas for which the brightness average value is notlarger than a predetermined value, comparing the number of divided areasfor which the brightness average value is not larger than apredetermined value to a threshold, and setting the gamma correctionsetting information according to whether or not the number of dividedareas for which the brightness average value is not larger than apredetermined value is less than the threshold.
 7. A Non-transitorycomputer-readable medium having stored thereon a computer-readableprogram for causing a computer to execute the steps of: receiving animage signal and setting information for each predetermined unit of theimage signal including gamma correction setting information to define agamma correction amount for the image signal; performing gammacorrection for the image signal based on the gamma correction settinginformation included in the setting information received in the step ofreceiving; and selectively performing a process to display the image forthe image signal corrected in the step of performing the gammacorrection based on the image type setting information included in thesetting information received in the step of receiving, wherein the gammacorrection setting information is determined by computing a brightnessaverage value for each of a plurality of divided areas of the imagesignal, determining a number of divided areas for which the brightnessaverage value is not larger than a predetermined value, comparing thenumber of divided areas for which the brightness average value is notlarger than a predetermined value to a threshold, and setting the gammacorrection setting information according to whether or not the number ofdivided areas for which the brightness average value is not larger thana predetermined value is less than the threshold.
 8. An image signalprocessing system, comprising: a transmitting device including a settingunit for setting gamma correction setting information to define a gammacorrection amount for the image signal to be transmitted for eachpredetermined unit of the image signal to be transmitted based on theimage signal to be transmitted, a transmission signal generating unitfor generating a transmission signal including the image signal to betransmitted and setting information for each predetermined unit of theimage signal to be transmitted including the image type settinginformation and the gamma correction setting information based on theimage signal to be transmitted and the set values for each predeterminedunit of the image signal to be transmitted set by the setting unit, anda transmitting unit for transmitting the transmission signal generatedby the transmission signal generating unit; and an image signalprocessing device including a receiving unit for receiving thetransmission signal, a gamma correcting unit for performing gammacorrection for the image signal included in the transmission signalreceived by the receiving unit based on the gamma correction settinginformation included in the setting information included in thetransmission signal received by the receiving unit, and an imageprocessing unit for selectively performing a process to display theimage for the image signal corrected by the gamma correcting unit basedon the image type setting information included in the settinginformation included in the transmission signal received by thereceiving unit, wherein the gamma correction setting information isdetermined by computing a brightness average value for each of aplurality of divided areas of the image signal, determining a number ofdivided areas for which the brightness average value is not larger thana predetermined value, comparing the number of divided areas for whichthe brightness average value is not larger than a predetermined value toa threshold, and setting the gamma correction setting informationaccording to whether or not the number of divided areas for which thebrightness average value is not larger than a predetermined value isless than the threshold.